scholarly journals Robust low friction performance of graphene sheets embedded carbon films coated orthodontic stainless steel archwires

Friction ◽  
2021 ◽  
Author(s):  
Zonglin Pan ◽  
Qinzhao Zhou ◽  
Pengfei Wang ◽  
Dongfeng Diao
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Orthodontic Treatment ◽  
Artificial Saliva ◽  
Carbon Film ◽  
Carbon Films ◽  
Graphene Sheets ◽  
Substrate Bias ◽  
Low Friction ◽  
Substrate Bias Voltage

AbstractReducing the friction force between the commercial archwire and bracket during the orthodontic treatment in general dental practice has attracted worldwide interest. An investigation on the friction and wear behaviors of the uncoated and carbon film coated stainless steel archwires running against stainless steel brackets was systematically conducted. The carbon films were prepared at substrate bias voltages from +5 to +50 V using an electron cyclotron resonance plasma sputtering system. With increasing substrate bias voltage, local microstructures of the carbon films evolved from amorphous carbon to graphene nanocrystallites. Both static and stable friction coefficients of the archwire-bracket contacts sliding in dry and wet (artificial saliva) conditions decreased with the deposition of carbon films on the archwires. Low friction coefficient of 0.12 was achieved in artificial saliva environment for the graphene sheets embedded carbon (GSEC) film coated archwire. Deterioration of the friction behavior of the GSEC film coated archwire occurred after immersion of the archwire in artificial saliva solution for different periods before friction test. However, moderate friction coefficient of less than 0.30 sustained after 30 days immersion periods. The low friction mechanism is clarified to be the formation of salivary adsorbed layer and graphene sheets containing tribofilm on the contact interfaces. The robust low friction and low wear performances of the GSEC film coated archwires make them good candidates for clinical orthodontic treatment applications.

scholarly journals Effects of Substrate Bias Voltage on Structure of Diamond-Like Carbon Films on AISI 316L Stainless Steel: A Molecular Dynamics Simulation Study

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4925
Author(s):  
Ngoc-Tu Do ◽  
Van-Hai Dinh ◽  
Le Van Lich ◽  
Hong-Hue Dang-Thi ◽  
Trong-Giang Nguyen
Keyword(s):  
Molecular Dynamics ◽  
Stainless Steel ◽  
Bias Voltage ◽  
Carbon Film ◽  
Carbon Films ◽  
Dynamics Simulation ◽  
Diamond Like Carbon ◽  
Substrate Bias ◽  
Aisi 316L ◽  
Substrate Bias Voltage

With the recent significant advances in micro- and nanoscale fabrication techniques, deposition of diamond-like carbon films on stainless steel substrates has been experimentally achieved. However, the underlying mechanism for the formation of film microstructures has remained elusive. In this study, the growth processes of diamond-like carbon films on AISI 316L substrate are studied via the molecular dynamics method. Effects of substrate bias voltage on the structure properties and sp3 hybridization ratio are investigated. A diamond-like carbon film with a compact structure and smooth surface is obtained at 120 V bias voltage. Looser structures with high surface roughness are observed in films deposited under bias voltages of 0 V or 300 V. In addition, sp3 fraction increases with increasing substrate bias voltage from 0 V to 120 V, while an opposite trend is obtained when the bias voltage is further increased from 120 V to 300 V. The highest magnitude of sp3 fraction was about 48.5% at 120 V bias voltage. The dependence of sp3 fraction in carbon films on the substrate bias voltage achieves a high consistency within the experiment results. The mechanism for the dependence of diamond-like carbon structures on the substrate bias voltage is discussed as well.

scholarly journals Multiscale frictional behaviors of sp2 nanocrystallited carbon films with different ion irradiation densities

Friction ◽  
2020 ◽  
Author(s):  
Zelong Hu ◽  
Xue Fan ◽  
Cheng Chen
Keyword(s):  
Friction Coefficient ◽  
Contact Pressure ◽  
Electron Cyclotron Resonance ◽  
Ion Irradiation ◽  
Carbon Film ◽  
High Hardness ◽  
Carbon Films ◽  
Real Contact Area ◽  
Low Friction ◽  
Plasma Sputtering

Abstract sp2 nanocrystallited carbon films with large nanocrystallite sizes, smooth surfaces, and relative high hardness were prepared with different ion irradiation densities regulated with the substrate magnetic coil current in an electron cyclotron resonance plasma sputtering system. Their multiscale frictional behaviors were investigated with macro pin-on-disk tribo-tests and micro nanoscratch tests. The results revealed that, at an ion irradiation density of 16 mA/cm2, sp2 nanocrystallited carbon film exhibits the lowest friction coefficient and good wear resistant properties at both the macroscale and microscale. The film sliding against a Si3N4 ball under a contact pressure of 0.57 GPa exhibited a low friction coefficient of 0.09 and a long wear life at the macroscale. Furthermore, the film sliding against a diamond tip under a contact pressure of 4.9 GPa exhibited a stable low friction coefficient of 0.08 with a shallow scratch depth at the microscale. It is suggested that sp2 nanocrystallites affect the frictional behaviors in the cases described differently. At the macroscale, the contact interface via the small real contact area and the sp2 nanocrystallited transfer layer dominated the frictional behavior, while the sp2 nanocrystallited structure in the film with low shear strength and high plastic resistivity, as well as the smooth surface morphology, decided the steady low nanoscratch properties at the microscale. These findings expand multiscale tribological applications of sp2 nanocrystallited carbon films.

Effect of Substrate Bias Voltage on the Mechanical and Tribological Properties of Low Concentration Ti-Containing Diamond Like Carbon Films

2012 ◽  
Vol 182-183 ◽  
pp. 232-236 ◽  
Author(s):  
Jin Feng Cui ◽  
Li Qiang ◽  
Bin Zhang ◽  
Xiao Ling ◽  
Jun Yan Zhang
Keyword(s):  
Bias Voltage ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Substrate Bias ◽  
Low Friction ◽  
Substrate Bias Voltage ◽  
Mechanical And Tribological Properties ◽  
Si Substrates ◽  
Argon Mixture ◽  
Hardness Values

Ti containing hydrogenated diamond like carbon films (Ti-DLC) was deposited on Si substrates at room temperature by magnetron sputtering Ti-twin target in methane and argon mixture atmosphere via changing the substrate bias voltage. The Ti atomic concentration in the film is less than 0.57% and exists mainly in the form of metallic titanium rather than TiC, confirmed by XPS analysis. The internal compressive stress of the film decreases monotonically with the substrate bias voltage increase. However, the hardness values of the film keep at level (12 GPa) without almost any obvious change with the increase of the substrate bias voltage. Furthermore, Ti-containing DLC film prepared at -1600 V substrate bias voltage shows an extremely low wear rate (~10-9mm3/Nm) and low friction coefficient (0.09).

scholarly journals Polyethylene glycol derived carbon quantum dots nanofluids: An excellent lubricant for diamond-like carbon film/bearing steel contact

Friction ◽  
2021 ◽  
Author(s):  
Fu Wang ◽  
Lunlin Shang ◽  
Guangan Zhang ◽  
Zhaofeng Wang
Keyword(s):  
Quantum Dots ◽  
Polyethylene Glycol ◽  
Friction Coefficient ◽  
Carbon Film ◽  
Carbon Quantum Dots ◽  
Bearing Steel ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Low Friction ◽  
Diamond Like Carbon Film

AbstractPolyethylene glycol derived carbon quantum dots nanofluids were synthesized via a slow thermal oxidation process. The size of carbon quantum dots was ca. 2 nm and had a decreasing trend with the increase of oxidation time. When used as lubricant in a diamond-like carbon film/bearing steel interface, the nanofluids achieved an ultra-low friction coefficient (μ ≈ 0.02), much lower than that of original polyethylene glycol (μ = 0.12). The worn surface analyses revealed that the nanofluids could effectively inhibit the tribo-oxidation of steel counterpart that occurred under original polyethylene glycol lubrication, and hence reduced the abrasion component of friction. Especially, the poly-hydroxyl carbon dots and oxidized polyethylene glycol species in nanofluids induced a hydroxyl-rich sliding interface via their tribochemical reactions with friction surfaces, which promoted the adsorption of polyethylene glycol molecules on sliding surfaces. Along with the mild corrosion wear of steel counterface, this shifted the boundary lubrication to a mixed/film lubrication regime, thereby achieving an ultra-low friction coefficient. The above results suggest that the polyethylene glycol derived carbon quantum dots nanofluids should be a quite excellent candidate lubricant for solid-liquid synergy lubrication based on diamond-like carbon films.

Temperature and Water Vapor Pressure Effects on the Friction Coefficient of Hydrogenated Diamondlike Carbon Films

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Pamela L. Dickrell ◽  
N. Argibay ◽  
Osman L. Eryilmaz ◽  
Ali Erdemir ◽  
W. Gregory Sawyer
Keyword(s):  
Water Vapor ◽  
Friction Coefficient ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
Carbon Film ◽  
Transient Behavior ◽  
Carbon Films ◽  
Pressure Effects ◽  
Diamondlike Carbon ◽  
Gas Surface Interactions

Microtribological measurements of a hydrogenated diamondlike carbon film in controlled gaseous environments show that water vapor plays a significant role in the friction coefficient. These experiments reveal an initial high friction transient behavior that does not reoccur even after extended periods of exposure to low partial pressures of H2O and O2. Experiments varying both water vapor pressure and sample temperature show trends of a decreasing friction coefficient as a function of both the decreasing water vapor pressure and the increasing substrate temperature. Theses trends are examined with regard to first order gas-surface interactions. Model fits give activation energies on the order of 40 kJ/mol, which is consistent with water vapor desorption.

Properties Oftetrahedralamorphous Carbon Films Deposited By the Filtered Cathodicarc Method

2002 ◽  
Vol 750 ◽  
Author(s):  
Naruhisa Nagata ◽  
Kazuhiro Kusakawa ◽  
Akiyasu Kumagai ◽  
Hideaki Matsuyama
Keyword(s):  
Mechanical Properties ◽  
Amorphous Carbon ◽  
Pyrolytic Graphite ◽  
High Hardness ◽  
Magnetic Film ◽  
Carbon Films ◽  
Substrate Bias ◽  
Substrate Bias Voltage ◽  
Tetrahedral Amorphous Carbon ◽  
Bond Ratio

ABSTRACTFirst, we studied the relation between the sp3 bond ratio and the hardness of 100-nm-thick tetrahedral amorphous carbon (ta-C) films deposited by a Filtered Cathodic Arc (FCA) system at different substrate bias voltages. For comparison, sputtered amorphous carbon (a-C) films and Highly Oriented Pyrolytic Graphite (HOPG) were also analyzed. According to the results, ta-C film deposited at a -70 volt substrate bias voltage had high hardness and high sp3 bond ratio of up to 88 GPa and 85%, respectively, whereas those of sputtered a-C were 29 GPa and 28%. Furthermore, we found that the hardness of carbon films, including sputtered a-C and HOPG, increased with increasing sp3 bond ratio. Based on this relation, the chemical bond structures of carbon films are considered to be closely related to their mechanical properties. Secondly, we investigated the relation between sp3 bond ratio and ta-C film thickness, over the range from 1 to 10 nm. The measurements showed that a 2-nm-thick initial layer grown on the surface of CoCrPt magnetic film had low sp3 bond ratios. It is suggested that this reduction in sp3 bond ratio in the initially grown layer seriously degrades the film's performance as a hard disk media overcoat. Further efforts to improve ta-C film processing will be required to improve its mechanical properties.

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